YBR125 top speed going down....

[richrock]

I'm due to get the bike in for a service anyway, but somethings bugging me -

Regular oil changes, maintenance is done regularly. However, in the last couple of weeks of riding I've noticed that my top speed along a flat section of my regular commute is decreasing.

I used to get 60-65mph+ depending is wind behind me. Now I'm getting 50-55mph and no more.

What's going on? I'm wondering if it just needs a tune (doesn't sound any different) or maybe the sparkplug needs changing...

And no, my weight hasn't changed -
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I has a motorbikes: Kawasaki GPZ500s (1999)- theory passed 12/06/12, test passed 10/07/12

[cb1rocket]

air filter? blocked possibly running rich, which doesn't appear to be mentioned. Do a plug chop (spark plug) and assessits condition.

is this the carb model by the way?

[Frost]

Could be the weather getting warmer. Engines make more power in cold air. A new plug couldn't hurt, nor could a new air filter and a minor adjustment of the mixture screw. The only other thing would be to get it compression tested, but thats a can of worms for another day

[cb1rocket]

Don't fiddle with the mixture screw at all, its only to adjust bottom end mixture - won't have any affect on top end other than hard starting.

Too many of us think this way, I do ave admit I thought this would have an affect on overall engine performance but its doesnt

[richrock]

Cheers chaps, wouldn't have thought of that. Got to get round to sorting the back brake (getting a bit stiff, common problem from what I've read), and I'll look at the air filter too.

How would I know if it's a carb model? All I know it's a 2008, but me and engines....
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I has a motorbikes: Kawasaki GPZ500s (1999)- theory passed 12/06/12, test passed 10/07/12

[N cee thirty]

iirc the 08 one is fuel injection so dunna touch it

oil change,valve clearances,check your wheels are going round smoothly and the brakes arn't catching and check ya tyre pressures
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30 Mod 2 Passed 09/06/2011

Jewlio Iglesias wrote: I actually did vote BNP once

[richrock]

Thanks!

Oil change - not due for another 400 miles, front wheel seems a little stiff, tyre pressures are good (check em weekly). Don't know how to check valve clearance, guess thats a mechanics job.

I'll mention it to the chaps on the service.
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I has a motorbikes: Kawasaki GPZ500s (1999)- theory passed 12/06/12, test passed 10/07/12

[bagger]